Monte Carlo model for nuclear collisions from SPS to LHC energies

A Monte Carlo model to simulate nuclear collisions in the energy range going from SPS to LHC, is presented. The model includes in its initial stage both soft and semihard components, which lead to the formation of color strings. Collectivity is taken into account considering the possibility of strings in color representations higher than triplet or antitriplet, by means of string fusion. String breaking leads to the production of secondaries. At this point, the model can be used as initial condition for further evolution by a transport model. In order to tune the parameters and see the results in nucleus-nucleus collisions, a naif model for rescattering of secondaries is introduced. Results of the model are compared with experimental data, and predictions for RHIC and LHC are shown.Comment: LaTeX, 48 pages, 6 tables, 15 postscript figures included using epsfi

Particle production azimuthal asymmetries in a clustering of color sources model

The collective interactions of many partons in the first stage of the collisions is the usual accepted explanation of the sizable elliptical flow. The clustering of color sources provides a framework of partonic interactions. In this scheme, we show a reasonable agreement with RHIC data for pT<1.5 GeV/c in both the dependence of v2 transverse momentum and in the shape of the nuclear modified factor on the azimuthal angle for different centralities. We show the predictions at LHC energies for Pb-Pb. In the case of proton-proton collisions a sizable v2 is obtained at this energy.Comment: To appear in Journal of Physics

Nuclear Effects in Charmonium Production in QCD

It is shown that the nuclear shadowing of charmonium due to the modification of the nuclear parton distribution is similar in the factorization approach based on non relativistic QCD and in the color evaporation model. In the first model, a separate study of the color octet and color singlet contributions to the yields of the various charmonium states as well as the contributions of these states to the total $J/\Psi$ production is performed. It is found a clear $x_F$ dependence of these contributions which can reproduce experimental data for moderate $x_F$.Comment: 11 pages, 5 Postscript figure

Genetic algorithms for the scheduling in additive manufacturing

[EN] Genetic Algorithms (GAs) are introduced to tackle the packing problem. The scheduling in Additive Manufacturing (AM) is also dealt with to set up a managed market, called “Lonja3D”. This will enable to determine an alternative tool through the combinatorial auctions, wherein the customers will be able to purchase the products at the best prices from the manufacturers. Moreover, the manufacturers will be able to optimize the production capacity and to decrease the operating costs in each case.This research has been partially financed by the project: “Lonja de Impresión 3D para la Industria 4.0 y la Empresa Digital (LONJA3D)” funded by the Regional Government of Castile and Leon and the European Regional Development Fund (ERDF, FEDER) with grant VA049P17Castillo-Rivera, S.; De Antón, J.; Del Olmo, R.; Pajares, J.; López-Paredes, A. (2020). Genetic algorithms for the scheduling in additive manufacturing. International Journal of Production Management and Engineering. 8(2):59-63. https://doi.org/10.4995/ijpme.2020.12173OJS596382Ahsan, A., Habib, A., Khoda, B. (2015). Resource based process planning for additive manufacturing. Computer-Aided Design, 69, 112-125. https://doi.org/10.1016/j.cad.2015.03.006Araújo, L., Özcan, E., Atkin, J., Baumers, M., Tuck, C., Hague, R. (2015). Toward better build volume packing in additive manufacturing: classification of existing problems and benchmarks. 26th Annual International Solid Freeform Fabrication Symposium - an Additive Manufacturing Conference, 401-410.Berman, B. (2012). 3-D printing: The new industrial revolution. Business Horizons, 55: 155-162. https://doi.org/10.1016/j.bushor.2011.11.003Canellidis, V., Dedoussis, V., Mantzouratos, N., Sofianopoulou, S. (2006). Preprocessing methodology for optimizing stereolithography apparatus build performance. Computers in Industry, 57, 424-436. https://doi.org/10.1016/j.compind.2006.02.004Chergui, A., Hadj-Hamoub, K., Vignata, F. (2018). Production scheduling and nesting in additive manufacturing. Computers & Industrial Engineering, 126, 292-301. https://doi.org/10.1016/j.cie.2018.09.048Demirel, E., Özelkan, E.C., Lim, C. (2018). Aggregate planning with flexibility requirements profile. International Journal of Production Economics, 202, 45-58. https://doi.org/10.1016/j.ijpe.2018.05.001Fera, M., Fruggiero, F., Lambiase, A., Macchiaroli, R., Todisco, V. (2018). A modified genetic algorithm for time and cost optimization of an additive manufacturing single-machine scheduling. International Journal of Industrial Engineering Computations, 9, 423-438. https://doi.org/10.5267/j.ijiec.2018.1.001Hopper, E., Turton, B. (1997). Application of genetic algorithms to packing problems - A Review. Proceedings of the 2nd Online World Conference on Soft Computing in Engineering Design and Manufacturing, Springer Verlag, London, 279-288. https://doi.org/10.1007/978-1-4471-0427-8_30Ikonen, I., Biles, W.E., Kumar, A., Wissel, J.C., Ragade, R.K. (1997). A genetic algorithm for packing three-dimensional non-convex objects having cavities and holes. ICGA, 591-598.Kim, K.H., Egbelu, P.J. (1999). Scheduling in a production environment with multiple process plans per job. International Journal of Production Research, 37, 2725-2753. https://doi.org/10.1080/002075499190491Lawrynowicz, A. (2011). Genetic algorithms for solving scheduling problems in manufacturing systems. Foundations of Management, 3(2), 7-26. https://doi.org/10.2478/v10238-012-0039-2Li, Q., Kucukkoc, I., Zhang, D. (2017). Production planning in additive manufacturing and 3D printing. Computers and Operations Research, 83, 157-172. https://doi.org/10.1016/j.cor.2017.01.013Milošević, M., Lukić, D., Đurđev, M., Vukman, J., Antić, A. (2016). Genetic Algorithms in Integrated Process Planning and Scheduling-A State of The Art Review. Proceedings in Manufacturing Systems, 11(2), 83-88.Pour, M.A., Zanardini, M., Bacchetti, A., Zanoni, S. (2016). Additive manufacturing impacts on productions and logistics systems. IFAC, 49(12), 1679-1684. https://doi.org/10.1016/j.ifacol.2016.07.822Wilhelm, W.E., Shin, H.M. (1985). Effectiveness of Alternate Operations in a Flexible Manufacturing System. International Journal of Production Research, 23(1), 65-79. https://doi.org/10.1080/00207548508904691Xirouchakis, P., Kiritsis, D., Persson, J.G. (1998). A Petri net Technique for Process Planning Cost Estimation. Annals of the CIRP, 47(1), 427-430. https://doi.org/10.1016/S0007-8506(07)62867-4Zhang, Y., Bernard, A., Gupta, R.K., Harik, R. (2014). Evaluating the design for additive manufacturing: a process planning perspective. Procedia CIRP, 21, 144-150. https://doi.org/10.1016/j.procir.2014.03.17

Respuestas de alimentación de Scolytus scolytus a extractos del floema de ramillas de olmo

Feeding responses by Scolytus scolytus were tested using elm twig bark extracts in a laboratory bioassay. One to 4- years-old elm twigs or small branches were sampled in spring and their bark extracted separately with methanol and with a mixture of petroleum ether and diethyl ether (1:1) as solvents. Bark extracts were tested in a two choice feeding bioassay consisting of two polyurethane discs placed in a 10 cm diameter Petri dish. Extracts were applied onto the discs and the amount of disc eaten by ten freshly emerged S. scolytus adults was recorded after 24 hours. Ten U. minor, two U. laevis, six U. glabra, three Dutch hybrids (European x Asiatic) and one U. pumila trees were tested in several comparisons. Discs with extracts from both U. laevis trees were significantly less eaten than those from U. pumila or from U. minor trees in two choice tests. Similarly, extracts from all U. glabra trees received less feeding than those from U. minor. On the contrary, S. scolytus showed no difference in feeding between U. pumila and U. minor extracts, and similarly for Dutch hybrids in comparison with two U. minor clones. Again, beetles preferred to feed on Dutch hybrid extracts better than in those from U. laevis. Significant intraspecific differences in feeding were obtained in U. minor. One of the U. minor clones resulted less chosen when compared to other four trees. Extracts from a dying U. minor tree received more feeding than those from a healthy tree. Comparisons were also made between bark extracts from 2-to 4-year-old vs. current-year twigs within the same trees. In one of the four U. minor tested, a significant preference for the older twig extracts was recorded.Se estudi&oacute; la respuesta de alimentaci&oacute;n de S. scolytus a extractos del floema de ramillas de olmo en bioensayos de laboratorio. Se muestrearon en primavera ramillas de olmo de uno a cuatro a&ntilde;os de edad y su floema fue extra&iacute;do independientemente con metanol o con una mezcla de eter de petr&oacute;leo y eter diet&iacute;lico (1:1). Los extractos del floema se evaluaron en un bioensayo de doble elecci&oacute;n consistente en dos discos de poliuretano dispuestos en una placa Petri de 10 cm de di&aacute;metro. Se aplicaron los extractos a los discos y se midi&oacute; la superficie de disco comida por diez adultos reci&eacute;n emergidos de S. scolytus durante 24 h. Se ensayaron diez U. minor, dos U. laevis, seis U. glabra, tres h&iacute;bridos holandeses (europeo x asi&aacute;tico) y un U. pumila en diversas comparaciones. Los discos con extractos de ambos U. laevis fueron significativamente menos comidos que aqu&eacute;llos con los de U. pumila o de U. minor. Igualmente, los extractos de todos los U. glabra recibieron menor alimentaci&oacute;n que aqu&eacute;llos de U. minor. Por el contrario, S. scolytus no mostr&oacute; preferencias entre los extractos de U. minor y de U. pumila, e igualmente, entre los de U. minor y los de h&iacute;bridos holandeses. Nuevamente, los escol&iacute;tidos prefirieron alimentarse menos de los extractos de U. laevis que de los h&iacute;bridos holandeses. Se encontraron diferencias intraespec&iacute;ficas significativas en U. minor. Uno de los clones de U. minor result&oacute; menos preferido cuando se le compar&oacute; con otros cuatro &aacute;rboles. Los extractos de un U. minor moribundo recibieron mayor alimentaci&oacute;n que los de un &aacute;rbol sano. Se realizaron comparaciones entre los extractos del floema de ramillas de 2 a 4 a&ntilde;os de edad y de ramillas del a&ntilde;o en curso de un mismo &aacute;rbol. En uno de cuatro U. minor ensayados se observ&oacute; una preferencia significativa por los extractos de las ramillas m&aacute;s viejas